Clear family - Ireland - Minnesota

I am trying to complete the Clear branch of my family tree: Philip Michael Clear (my ggrandfather) and his sister Mary Catherine Clear left Ireland around 1850 and came to North America (probably US but maybe Canada).Philip married Margaret Catherine Wing and he and his wife are listed in the Minnesota 1860 census, living in Lakeland, Washington County.Then I can't locate him in any records until his death in Washington state in 1919.I would really like to know what county he and his sister came from in Ireland.My grandmother mentioned another relative in Kilkenny -- that is the only information I have.Can anyone help?